When you get blood work, your results arrive with reference ranges. Understanding those numbers can feel empowering. This guide walks through the most common lab values and what each one checks. First, though, one rule matters above all: ranges vary by lab, and only your doctor can interpret your results. This is general information, not medical advice.
Why Reference Ranges Vary
Every lab sets its own reference ranges. They depend on the equipment, the method, and the population tested. Ranges can also shift with age and sex.
So your own lab report is the source of truth. It lists its range right next to your result. A value slightly outside the range is common and often harmless. Doctors read results together, not one at a time.
Complete Blood Count (CBC)
The CBC looks at your blood cells. It helps detect anemia, infection, and clotting problems. Here are typical adult ranges.
Hemoglobin runs about 13 to 18 g/dL in men and 12 to 16 in women. Hematocrit runs about 40% to 55% in men and 36% to 48% in women. White blood cells run about 4,500 to 11,000 per microliter. Platelets run about 150,000 to 400,000.
Low hemoglobin may suggest anemia. A high white count may suggest infection. But context always matters, so your doctor interprets the pattern.
Basic Metabolic Panel (BMP)
The BMP checks your body chemistry. It assesses kidney function, electrolytes, and blood sugar. Typical ranges follow, in the units your lab uses.
Sodium runs about 136 to 144. Potassium runs about 3.7 to 5.2. Chloride runs about 96 to 106. Carbon dioxide runs about 23 to 29.
The panel also includes fasting glucose around 64 to 100, BUN around 6 to 20, creatinine around 0.8 to 1.2, and calcium around 8.5 to 10.2. Together these flag problems with the kidneys, hydration, and blood sugar.
Liver and Other Common Tests
Many people also get a liver panel. It includes enzymes like AST and ALT, plus bilirubin and albumin. High liver enzymes can point to liver stress or damage.
A thyroid test, called TSH, checks how your thyroid is working. And a lipid panel measures cholesterol, which we cover next.
Cholesterol and A1C
Some results use standard cutoffs rather than lab-specific ranges. For total cholesterol, below 200 is desirable, 200 to 239 is borderline high, and 240 or above is high. Doctors also look at LDL, HDL, and triglycerides together.
The hemoglobin A1C reflects your average blood sugar over months. Below 5.7% is normal. From 5.7% to 6.4% is prediabetes. And 6.5% or higher points to diabetes.
What Can Affect Your Results
Several everyday factors move lab values. Recent meals and hydration can shift them. So can exercise, stress, medications, and even the time of day.
This is one reason some tests require fasting. It is also why a single odd result may mean little. Your doctor accounts for these factors when reading your labs.
How to Read Your Results Wisely
Start with the reference range printed on your report. Then resist the urge to diagnose yourself. A number outside the range is not automatically a problem.
Instead, bring questions to your provider. Ask what a result means for you specifically. Your doctor sees the whole picture, including your history and symptoms. That context is what turns numbers into meaning.
Urinalysis and Other Tests
Blood tests are not the only lab work you may see. A urinalysis checks your urine for protein, blood, sugar, and signs of infection. It adds useful information about your kidneys and health.
Other common tests include a coagulation panel, which measures clotting, and thyroid tests. Your doctor orders the tests that fit your situation.
What “Critical Values” Mean
Some results are flagged as critical. These are values far outside the normal range. They can signal a serious, urgent problem.
A lab will alert your doctor quickly about a critical value. Your provider then decides on next steps. This safety system helps catch dangerous results fast.
Normal Lab Values FAQs
What are normal lab values?
Typical reference ranges for blood tests. They vary by lab and must be interpreted by your doctor.
Why do ranges differ between labs?
Labs use different methods and equipment, so each lists its own range on your report.
Is a result outside the range always bad?
No. Being slightly outside a range is common and often harmless, which is why context matters.
What does a CBC check?
Your blood cells, including hemoglobin, hematocrit, white blood cells, and platelets.
What does a metabolic panel check?
Body chemistry like sodium, potassium, glucose, kidney markers, and calcium.
Do food and hydration affect results?
Yes. Meals, hydration, exercise, and medications can all shift results.
What is the A1C test?
It reflects average blood sugar. Below 5.7% is normal, 5.7% to 6.4% is prediabetes, and 6.5% or higher is diabetes.
Should I interpret my own labs?
No. Ask your doctor, since results are read together and in the context of your health.
